Search Google Appliance

Squares & Triangles

T-Squares

Some of the T-squares are shaped like Ls or have calipers. The examples in the collection range from simple, crudely constructed instruments to well-made, mass-produced T-squares. The newest object was for use at the blackboard in a mathematics classroom.

In 1876 the Japanese Empire Department of Education exhibited many instruments at the Centennial International Exhibition, a World’s Fair held in Philadelphia. After the exhibition, John Eaton, the U.S. Commissioner of Education, arranged for the transfer of Japan's entire exhibit—including this object—to the Bureau of Education (then part of the Department of the Interior) for a planned museum. The museum closed in 1906, and much of the collection was transferred to the Smithsonian in 1910.

On one side, this 18-1/2" L-shaped brass instrument is divided along the outside of its short leg into 7.5 units of 1-3/16" (3 cm). Each unit is thus roughly equivalent to the sun, a traditional Japanese unit of length that is 1/10 of a shaku, a "foot" measure. The units are subdivided into 10 parts. The fifth unit is marked with an arrangement of five dots.

The outer edge of the long leg is divided into ten units of 1-3/4" (4.3 cm). Each unit is subdivided into tenths. From the right, the fifth and tenth units are marked with an arrangement of five dots. The other units are marked with single dots. A single dot also marks the 0.9 points. Groups of three dots mark the 3.55 and 7.05 points, and another group of three dots marks a point to the left of the divisions on the scale.

The inner edge of the long leg is divided from left to right into five units of 1-13/16" (4.5 cm) and five sun. The larger units are marked with Japanese characters. The sun are subdivided into tenths and marked with single dots, except for the fifth unit, which is marked with five dots.

On the other side, the outer edges of both legs are divided into sun subdivided into tenths. The midpoint of each unit is marked with three dots. The fifth, tenth, and fifteenth units from the vertex are marked with five dots. The instrument was designed for measuring lengths, drawing right angles, and determining whether two lines are perpendicular to one another.

This 6-1/2" brass T-square is composed of two L-shaped brass pieces. The bottom piece slides along a groove in the long leg of the top piece. The outer edges on one side and the inner edges of the other side of all four legs are divided into units of 1-3/16" (3 cm). Each unit is thus roughly equivalent to the sun, a traditional Japanese unit of length that is 1/10 of a shaku, a "foot" measure. The units are subdivided into 50 parts. Whole and half-units are marked with zeroes.

The instrument was designed for measuring lengths, drawing right angles, and determining whether two lines are perpendicular to one another. When the two pieces are pulled apart, the instrument also functions as a caliper, to measure the width of a small object or the dimensions of part of a finished drawing. The English workshop of George Adams Jr. made a similar instrument from wood and brass in the late 18th century. Compare also to MA*261304 and to caliper rules such as MA*261299 and 1990.0099.01.

In 1876 the Japanese Empire Department of Education exhibited many instruments at the Centennial International Exhibition, a World’s Fair held in Philadelphia. After the exhibition, John Eaton, the U.S. Commissioner of Education, arranged for the transfer of Japan's entire exhibit to the Bureau of Education (then part of the Department of the Interior) for a planned museum. The museum closed in 1906, and much of the collection, including this object, was transferred to the Smithsonian in 1910.

This 8" brass T-square is shaped like an L and has a second short leg attached to a slide on the long leg. On one side, the outer edge of the square is divided into units of 1-3/16" (3 cm), roughly equivalent to the sun, a traditional Japanese unit of length. Each unit is subdivided into 20 parts. The units on the long leg are marked with an O, with three circles marking the fifth unit. The inner edge of the long leg has a 15-centimeter scale, divided to millimeters. The back of the square has a diagonal scale. Compare to MA*261296.

In 1876 the Japanese Empire Department of Education exhibited many instruments at the Centennial International Exhibition, a World’s Fair held in Philadelphia. After the exhibition, John Eaton, the U.S. Commissioner of Education, arranged for the transfer of Japan's entire exhibit to the Bureau of Education (then part of the Department of the Interior) for a planned museum. The museum closed in 1906, and much of the collection, including this object, was transferred to the Smithsonian in 1910.

A wooden bar (6-1/8" x 2" x 3/4") is attached to a flat wooden handle (17-7/8" x 2" x 1/8") by nine wooden pegs. By the 17th century, draftsmen used T-squares to help them draw horizontal lines. The instrument was also used in conjunction with a set square or triangle to draw vertical and diagonal lines. The dating of other objects from this donor suggests this object was made about 1900. Compare to MA*328397 and MA*328398.

This 19" wooden T-square has a curved top piece attached to the handle by two steel screws. The back of the top piece has a ridge for positioning against a table. A hole at the end of the handle is for hanging the instrument. It has no markings. The dating of other objects from this donor suggests this object was made about 1900. Compare to MA*328396 and MA*328398.

This 51-1/2" wooden T-square has a scalloped top piece attached to the handle by 6 brass screws. A hole at the end of the handle is for hanging the instrument. It has no markings, but paint and ink stains on the handle indicate it was heavily used. The dating of other objects from this donor suggests this instrument was made about 1900. Compare to MA*328396 and MA*328397.

The 18" X 24" drawing board is made of six strips of pine, joined with tongue and groove construction to two pine endpieces. The board is pieced to allow for expansion and contraction. It is not marked. Between 1926 and 1938, the Eugene Dietzgen Company added this size of board to its model 4410 line of drawing boards.

The 26-3/8" ash T-square is lined with maple on the handle. The head is 13" wide and painted black. The handle is marked: DIETZGEN (/) GLOBE (/) 12066-24. A drawing of the Earth appears around the word "GLOBE." A round hole at the end of the handle permits hanging. Between 1926 and 1938, Dietzgen began offering a "school quality" version of its model 2066 line of T-squares and gave that version the model number 12066.

George Norton (1927–2009) purchased these tools in 1944 as part of a "practical drawing outfit" (model number 1100BW) that also included two celluloid triangles, a triangular scale, a celluloid protractor, a celluloid French curve, a box of thumb tacks, two pencils, one eraser, one art gum, one pencil pointer, twelve sheets of sandpaper, one bottle of black ink, six sheets of drawing paper, one instruction book, and a lettering chart. He paid $4.60 for the entire boxed kit. He used the instruments as a toolmaker for the U.S. Naval Gun Factory in Washington, D.C. He worked for the Smithsonian from the early 1960s until 1989.

This 13" white plastic T-square is marked on the handle: STERLING – 542. It is also marked: MADE USA. The handle has a scale of 12 inches, divided to 1/16" and numbered by ones from 1 to 12, and a 30.5 centimeter scale, divided to millimeters, numbered by ones from 1 to 30, and marked: MM. A hole near the end of the handle permits hanging.

George and Mary Staab operated Sterling Plastics in Mountainside, New Jersey, from 1938 through the late 1960s. The firm was a division of Borden Chemical Company in the 1970s and 1980s and was purchased by Sanford Corporation in 1988. See also MA*335327, 1988.0807.01, 1990.0689.01, and 1998.3104.01. Isaac Giacinto Molella, who worked as an electrical engineer for General Electric in the United States, North Africa, and Europe in the 1950s, previously owned this T-square.

This 27" aluminum and plastic T-square has scales of inches along both sides of the handle. One scale is divided to 1/8" and the other is divided to 1/16". Both scales are numbered by ones from 1 to 24. The end of the handle has a hole for hanging. The handle is marked: FAIRGATE 115–T. It is also marked: COLD SPRING, N.Y. 10516 MADE IN U.S.A.

The blue plastic crosspiece has holes in its interior. The lower edge of the crosspiece is marked with a scale of units slightly longer than one inch, divided to eighths and numbered by ones from 1 to 5 on both sides of the handle. The back of the crosspiece is marked: FAIRGATE (/) COLD SPRING NY (/) MADE IN U.S.A.

This instrument was found in the collections in 1984. The Fairgate Rule Company began manufacturing high-quality aluminum scale rules, T-squares, L-squares, templates, and curves in Cold Spring, N.Y., in 1946 and remains in business as of 2013. This particular T-square is now sold as model number 63-124 for $14.10.

Along its top edge, this 9-1/2" transparent orange plastic rectangular instrument has a scale of inches divided to 1/16" for four inches and to 1/10" for four inches and numbered by ones from 1 to 8. The bottom edge has a centimeter scale divided to millimeters and numbered by ones from 0 to 20. Two rectangular indentations running the length of the instrument have holes drilled every 1/2-inch for drawing vertical lines. The holes are numbered from 3-1/2" to 0" to 3-1/2".

A lip underneath the instrument's left end serves as a guide rail when the T-square is placed on the edge of a clipboard or drawing board. Unlike a conventional T-square, this object has no crosspiece. This was supposed to make it easier to use. A hole at the right end permits hanging or placement in a three-ring binder. The device is marked: VIEW THRUTM; SAFE-T T-SQUARE®; SAFE-T PLASTIC®. It is also marked: Pat. (/) Pend. This patent was not identified.

Safe-T Products, Inc., of La Grange, Ill., was established in 1992 to sell drawing instruments that were safe for schoolchildren. In 1998 and 2000, Safe-T sold model 41516 for $1.95. In 2006, the company became a subsidiary of A. Daigger & Company and its name changed to Classroom Products Warehouse.